The present invention relates to a switch system, a line card, a learning method of FDB information and a program therefor.
In a layer-2 switch that is configured of a plurality of line cards 601, 602, 603, and 604, as shown in FIG. 7, the switch apparatus includes line cards that have FDB tables 702, 712, 722 and 732, respectively.
Normally, when the line card 601 receives a certain packet, a packet processor 701 of the line card 601 references the FDB table 702, determiners whether the above packet is a unlearned packet, defines it as a packet that has to be learned when it is a unlearned packet, and transfers a learning notification to an FDB buffer 704.
A CPU 703 reads out the learning notification from the FDB buffer 704, and registers it to the FDB table 702. At this time, all FDB tables need to have identical information in synchronization to each other, whereby the CPU 703 transfers the similar learning notification to the other line cards 602, 603, and 604, and CPUs 713, 723, and 733 of other line cards 602, 603, and 604 register the learning notification to the FDB tables 712, 722 and 732 with the similar process, respectively.
When the line card having received the packet is 602, the CPU 713 performs the similar process. In such a configuration, when the packets being newly received concentrate on a single line card, the CPU of the above line card needs to perform the process of the packets that the above line card itself receives, and the process of the packets that are received from the other line cards, and thus, a load on the CPU is likely to be biased.
Further, there exists the problem that when the learning notification for synchronization being transmitted inside the apparatus and the learning notification for the packet received from the outside are congested with each other, the learning notification cannot be accumulated into the FDB buffer and is cancelled, disagreement of the FDB tables is brought about inside the apparatus, and hence, the packets cannot be normally transferred.
Further, the above line card firstly learns and then makes a notification to the other line cards, and such a congestion situation incurs the case that while above line card has already learned, the other line cards have not learned yet, which causes the problem that disagreement of the FDB tables is brought about.
So as to solve such problems, the invention of Patent literature 1 is proposed.
The switch apparatus described in the Patent literature 1 includes a first card having a L2SW (layer 2 switch) installed therein and a second card. And, in the case of having detected the FDB information that is not present in its own switch, the first card transmits it to the second card, and updates the FDB information of its own switch with the FDB information being transmitted from the second card. Further, the second card collects the FDB information being transmitted from each first card, updates the FDB information of the switch apparatus, and transmits the updated FDB information to each card.
Patent literature 1: JP-P2010-177722A
However, the invention of Patent literature 1 requires a memory for storing the FDB information of each card by the second card collecting the FDB information, and further, includes the layer 2 switching processor to which a special function has to be affixed.